From 2fe3f1100e2252a79cebeabfd2bca3d1817acaee Mon Sep 17 00:00:00 2001 From: Justin Paul Date: Mon, 29 Jun 2026 21:51:58 -0400 Subject: [PATCH] diagnostics: FICM healthy (>48V), ether-start signature narrows to ICP path - FICM measured >48V on M during cranking AND key-ON. Healthy. Removed as a suspect. - Truck starts cleanly on starting fluid (ether) every time, then idles and runs normally until shut off -- then needs ether again, even when warm. This is a textbook signature for high-pressure oil (ICP) bleed during cranking that the HPOP can outrun at running RPM. - Updated working hypothesis to focus on STC fitting / oil rail O-rings / HPOP / IPR. Compression, FICM, CMP/CKP, fuel supply all confirmed good by virtue of the engine running cleanly once started. - Reordered open items to put visual inspection of valve covers + STC fitting first. Co-Authored-By: Claude Opus 4.7 --- diagnostics/2026-06-29-no-start/README.md | 107 +++++++++++++++++----- handoff.md | 21 +++-- 2 files changed, 97 insertions(+), 31 deletions(-) diff --git a/diagnostics/2026-06-29-no-start/README.md b/diagnostics/2026-06-29-no-start/README.md index 9b01dd7..d851332 100644 --- a/diagnostics/2026-06-29-no-start/README.md +++ b/diagnostics/2026-06-29-no-start/README.md @@ -27,19 +27,69 @@ No engine P-codes, no FICM codes, no injector codes, no CMP/CKP codes. (see `watch-cranking.log`). Bus sagged to 10.8–11.2V during ~11s crank, borderline-low but not catastrophic. Healthy starter spin means batteries have current to give. -- **Fuel supply** — HFCM lift pump audibly primes and shuts off correctly - on key-RUN. +- **Fuel supply (low-pressure)** — HFCM lift pump audibly primes and shuts + off correctly on key-RUN. And the truck runs fine once started, so the + whole fuel-supply chain delivers under load. - **Compression / mechanical** — fast even cranking, would feel different - with a low-compression cylinder. + with a low-compression cylinder. Ether ignition (see below) confirms + good compression and valve timing. +- **FICM** — meter showed **>48V on cranking AND key-ON**. FICM is healthy. +- **Injector electrical / CMP / CKP** — truck runs fine once started, so + injector drive, cam/crank sync, and the FICM-to-injector path are all + good when the engine is turning at running RPM. + +## ⭐ Key diagnostic finding: ether starts it every time + +Spraying starting fluid (ether) into the intake **gets the truck to fire, +catch, and run normally** — and it then **idles and runs fine until shut +off**. Then it needs ether *again* to restart, even when warm. + +This is a near-textbook signature on a 6.0: + +- Ether ignites at much lower temperature and pressure than diesel. If + the engine fires and runs on ether, **compression, timing, and valves + are fine**. +- If it runs cleanly once started, **injectors are firing correctly at + running ICP** and the high-pressure oil system is making enough + pressure *at running RPM* to drive the injectors. +- Needing ether **every** time — even after warm-up — means the failure + is in the **starting-pressure window**, not a cold-soak / temperature + issue. + +Mechanism: at cranking RPM the HPOP can only generate ICP so fast. +Anything that bleeds high-pressure oil at cranking speeds will starve +ICP below the ~500 psi firing threshold. Once the engine catches (on +ether) and gets to idle RPM, the HPOP can outpace the leak and ICP +holds normal — so it runs fine. Shut it off, oil pressure drops to +zero, the leak path is still there next crank. ## Working hypothesis (in order of suspicion) -1. **ICP / high-pressure oil leak** — STC fitting is the classic 6.0 culprit - for "cranks great, won't fire, no codes". Need ≥500 psi ICP to fire even - one injector. -2. **FICM weakness** — should boost to ~48V. Sometimes doesn't throw a code - even when failing. **Not yet measured** — see open items. -3. **CMP sensor** — would usually throw P0340/P0341 but not always. +The new symptom set narrows the field hard. **It is almost certainly +in the high-pressure oil (ICP) path that feeds the injectors:** + +1. **STC fitting** — the high-pressure oil branch tube where it joins + the oil rails. Classic 6.0 wear item. Cracks at the fitting let oil + bleed off during cranking when the HPOP can't keep up; pressure + recovers at running RPM. Ford TSB exists. **#1 suspect.** +2. **High-pressure oil rail O-rings** (under the valve covers) — same + failure mode: leak at cranking pressure, mask at running pressure. +3. **HPOP discharge tube / O-rings** — same family. +4. **IPR valve** seat/seal worn or stuck — bleeds oil back to sump + during cranking. +5. **HPOP itself worn** — gears can't pressurize fast enough at + cranking RPM. Less common than STC/rails. +6. **Sticky injector spool valves** — some 6.0 injectors won't open at + marginal ICP but work fine once pressure is up. Less likely if it + needs ether *every* time, more likely if it's "some cold starts." + +What this is **NOT** (given runs-fine-once-started + needs-ether-even-warm): +- ❌ FICM (measured >48V; also injectors fire fine when running) +- ❌ CMP/CKP (sync is good when running) +- ❌ Glow plugs / glow plug control (needing ether when *warm* rules + this out — warm engine doesn't need glow assist) +- ❌ Fuel filters / HFCM / lift pump (runs fine = fuel delivery works) +- ❌ Compression / valve seal (ether fires and engine runs cleanly) ## What we did with the tool this session @@ -88,21 +138,30 @@ To know what each one *is*, compare against a known measurement: ## Open items / what's next -1. **FICM meter test was started but no readings reported back yet.** - Measure M / S / L on the FICM body, key-ON and during a (short) crank: - - M (Main) target ~48V cranking, <45V suspect, <40V dead - - S (Sync) target ~48V cranking - - L (Logic) target ~12V (mirrors battery) -2. **Visual under-engine check** for STC-fitting oil leak (wet/oily mess - at the rear of the engine, around the turbo / bell housing). -3. **Verify scan-hit PIDs.** Re-probe the clean ones above with - `--pid XXXX` to get uncontaminated readings, log them against known - conditions. -4. **Try addressing other modules with `ATSH`** — particularly the FICM - on its CAN address if it has one (uncertain on 6.0 — likely on SCP). -5. Try **FORScan** when forscan.org / CyanLabs mirror is back, on the - same CH340 adapter, to capture FORScan's actual PID requests for - ICP/FICM/IPR. That gives us the ground truth. +Order is now: confirm the ICP-side leak source, then fix. + +1. **Visual inspection under valve covers / around STC fitting.** + Pull both valve covers and look for oil flooding, weeping at the + STC fitting (high-pressure oil branch tube), and the condition of + the high-pressure oil rail O-rings on each head. +2. **Crank and watch ICP build** (once we have a verified ICP PID, or + with FORScan / IDS). A healthy 6.0 builds ~500+ psi in 1–2 seconds + of cranking. If ours stalls below 500 psi or builds very slowly, + that confirms the high-pressure leak. +3. **Verify scan-hit PIDs.** Re-probe the cleanest hits with + `--pid XXXX` (`1310`, `1440-1451`, `11Bx` cluster) for uncontaminated + readings. The cluster around `1440-1451` looks like a related sensor + group — could include ICP_V / IPR / ICP_DES if we're lucky. +4. **FORScan** via CyanLabs mirror when it's back, on the same CH340. + With ICP and IPR live data in front of us, the leak source is much + easier to nail down (e.g., IPR commanded high but ICP stays low = + leak; IPR low and ICP low = control side). +5. **Optional cheap check**: pull the IPR valve and inspect the seat + for wear / debris / a stuck pintle. ~$0, takes 15 minutes. +6. **Address other modules with `ATSH`** — particularly trying the FICM + on its CAN address if it has one (uncertain on 6.0 — FICM likely on + SCP, not directly reachable from OBD-CAN). Lower priority now that + FICM is confirmed healthy by meter. ## Tool state at end of session diff --git a/handoff.md b/handoff.md index e3e5c35..89ea73c 100644 --- a/handoff.md +++ b/handoff.md @@ -51,8 +51,12 @@ The 6.0 needs, to fire: **good batteries → FICM ~48V → ICP ~500 psi → fuel - **2026-06-29 in-cab session:** added `--watch`, `--ford`, `--pid`, and `--scan` modes. Captured cranking voltages + ran a Mode-22 brute scan (46 PIDs hit). Full session writeup + raw data in [diagnostics/2026-06-29-no-start/](diagnostics/2026-06-29-no-start/README.md). - **Headline:** not batteries, not fuel — almost certainly ICP / FICM / CMP. - **Unfinished:** FICM meter test on M/S/L was started but readings never logged. + **Headline:** FICM measured >48V (healthy). Truck **starts on ether every + time** and runs/idles fine until shut off — then needs ether again. That + signature ⇒ **high-pressure oil (ICP) bleed-off during cranking** — STC + fitting / oil rail O-rings / HPOP-related. Compression, FICM, CMP/CKP, + fuel supply all confirmed good. Next: visual under valve covers + STC + fitting inspection. - Pushed to `git.jpaul.io/justin/ford-obd`, branch `main`. Files: `obd_reader.py`, `RUN_OBD.bat`, `README.md`, `README.txt`, `handoff.md`, `diagnostics/`. @@ -63,11 +67,14 @@ no-crank, hot vs. cold, what changed before it died, and FICM/ICP readings if yo ## To resume from the desktop (after the 2026-06-29 session) Read [diagnostics/2026-06-29-no-start/README.md](diagnostics/2026-06-29-no-start/README.md) -first — that's the full state. Top open items: -1. Get FICM M/S/L meter readings (key-ON and during a short crank). -2. Re-probe the clean scan hits (1310, 1440-1451, 11Bx) with `--pid XXXX` - for uncontaminated data, then map them to known engine conditions. -3. Look at FORScan via the CyanLabs mirror to capture ground-truth PIDs. +first — that's the full state. Top open items, in order: +1. **Visual under valve covers + STC fitting** — looking for the high-pressure + oil bleed source. That's where the diagnosis lands. +2. Re-probe the clean scan hits (`1310`, `1440-1451`, `11Bx`) with `--pid XXXX` + for uncontaminated data; map them to known engine conditions to identify + ICP / IPR. +3. FORScan via the CyanLabs mirror once available — ICP and IPR live data + would confirm a high-pressure leak in seconds. ## Open follow-ups (when off the truck) - FORScan from the CyanLabs mirror once forscan.org is back — useful as the